Injection molding machine



Jan. 1, 1963 Filed Aug. 6, 1959 H. AF. JURGELEIT INJECTION MOLDING MACHINE 10 Sheets-Sheet 1 BY www ATTORNEY Jan. 1, 1963 H. F. JURGELl-:IT 3,070,843

INJECTION MOLDING MACHINE Filed Aug. 6, 1959 v 10 SheebS-Sheet 2 1N VEN TOR.

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ATTORNEY Jan. l, 1963 H. F. JURGELEIT 3,070,843

` I INJECTION MOLDING MACHINE Filed Aug. 6, 1959 10 Sheets-Sheet 3 JNVENToR.

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INJECTION MOLDING MACHINE Filed Aug. e, 1959 1o sheets-sheet 4 ATTORNEY" Jan. 1, 1963 H. F. JURGELEIT INJECTION NOLDING MACHINE 10 Sheets-Sheet 5 Filed Aug. 6, 1959 JNVENTOR. Hf/fami E uma/5.4 E/

BY y r6- ATTORNEY Jan. 1, 1963 H. F. JURGELEIT 3,070,843

INJECTION MoLDING MACHINE Filed Aug. 6, 1959 10 Sheets-Sheet 6 244 if? 5f iff fr w J l l I I l ATTORNEY Jan. l, 1963 H. F. JURGELEIT 3,070,843

INJECTION MOLDING MACHINE Filed Aug. 6, 1959 10 Sheets-Sheet '7 ATTORNEY Jan. l, 1963 H. F. JURGl-:LEIT 3,070,843

INJECTION MOLDING MACHINE Filed Aug. e, 1959 1o sheets-sheet e Q Q 1 I SQ www 3% NNW mjwwmm.- 4% N. www f im QN@ www.

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INJECTION MOLDING MACHINE Filed Aug. 6, 1959 10 Sheets-Sheet 9 ATTORNEY fz /4 w /4/ Jan. 1, 1963 H. F. JURGELEYIT INJECTION MOLDING MACHINE 10 Sheets-Sheet 10 Filed Aug. 6, 1959 3,070,843 patented Jan. l, 1963 3,070,543 lNlECTlN MOLDING MACHiNE Herbert F. .lurgeleit, Oceanside, NX., assigner to United States Rubber Company, New York, NX., a corporation of New Jersey Filed Aug. 6, 1959, Sel'. No. 832,042 Claims. (Cl. 18-20) This invention relates to automatic molding machines, and in particular to an automatic, duplex, rotary turret injection molding machine.

Injection molding operations as presently carried out by means of known molding machines or in accordance with known processes are generally beset by a number of difficulties and entail large expenditures of time and labor by constantly required operators and supervisory personnel. One of the operational difficulties invariably encountered is the formation of ash between insufficiently clamped mold plates during the curing of the injected molding compound resulting from the thermal expansion of the latter. 'Ihe basic reason for this drawback of known machines and processes is that it has heretofore been deemed technically impracticable and thus uneconornical to provide means for exerting the necessary clamping pressures during the curing stage so as to ensure a ashless operation. A further operational difficulty generally encountered is the occurrence of molding scrap losses, especially in molding operations of the b-ottomless cylinder type. As is well known, in such operations the injection piston or plunger engages a mass of a molding compound, which is located in a substantially bottomless cylindrical cavity, and forces this compound against the sprue plate of a mold. In this manner, although a great amount of the compound is forced through the sprues of the sprue plate into the mold cavity or cavities, there always remains a sheet or blanket of the compound between the piston and the sprue plate at the end of the injection stroke of the former. This blanket of molding compound represents a complete waste and, since it is usually cured with the injected material, cannot be recovered for use during a subsequent injection operation.

Moreover, the known molding processes (automatic, semi-automatic and non-automatic) based on the injection, cavity-stuffing or compression molding principles are characterized by a number of serious drawbacks, including not only the above-mentioned high molding scrap losses and flash formation, but also high molding labor and supervision expenses, high costs of trimming, finishing and inspecting the molded articles, high mold maintenance costs, etc.

Still further, known rotary turret injection or compression molding machines are generally equipped with only one turret and one set of molds, whereby it is not feasible to increase production rate and efficiency for each machine beyond a certain limit. Thus, mass production techniques, especially for small items in great demand, require the use of a great number of molding machines each with its own set of controls and associated mechanisms, which means a considerable waste of iioor space and naturally entails the expenditure of much needless time, labor and money.

It is, therefore, one of the important objects of the present invention to provide an automatic injection molding machine which is free of the `drawbacks and disadvantages inherent in known injection molding machines and yet offers all the combined advantages of such known machines.

It is another important object of the present invention to provide an automatic molding machine in which the injection operation is effected by a modified bottomless cylinder arrangement without the usually encountered scrap losses of molding compound.

Another object of the present invention is the provision of such a molding machine in which the molds are of the multi-plate type and are so constructed and arranged that the various plates of each mold can be clamped together either resiliently or hydraulically with sufficient force to prevent any formation of flash between the plates Without rendering the production of molded parts uneconomical.

Still another object of the invention is the provision, in a molding machine of this type, of means for preventing the occurrence of backrinding or other defects in the molded articles, and also of novel means for ejecting or extracting the molded articles from the molds simultaneously with a clearing of the sprues thereof.

A further object of the present invention is the provision of a compact duplex injection molding machine which is possessed of great versatility in the types of mold parts it can accommodate and in the shapes'and sizes of articles which can be produced thereby, and which leads to considerable operating and manufacturing economies.

It is also an object of the present invention to provide novel and highly efficacious means for feeding the molding compound or stock to the injection units of an injection molding machine as aforesaid in accordance with the consumption of the stock, as Well as to provide means for isolating the injection units from the rotary turrets at all times except during an actual injection operation.

Yet another important object of the present invention is the provision of multi-plate mold constructions and either cam-actuated or hydraulically actuated means for opening and closing the molds which render the mold plates substantially free of uneven wear at the contact surfaces thereof and thus greatly enhance the useful life of each mold.

The foregoing and other objects, characteristics and advantages of the present invention will be more fully understood from the following detailed description thereof when read in conjunction with the accompanying drawings, in which:

FIG. l is a vertical front elevational view of an injection molding machine constructed in accordance with the present invention;

FIG. 2 is a vertical sectional view taken along the line 2-2 in FIG. 1 and illustrates details of the structure of the mold wheel or turret arrangement, the three-plate molds carried by the wheels, the mold wheel indexing mechanism, and the stock feeding and injection means, some of the parts being shown in elevation;

FIG. 3 is a longitudinal sectional view of the mold opening and closing means associated with spring type mold clamping means, the anti-backrinding means, and the injection unit associated with one of the mold Wheels or turrets of the machine;

FIG. 4 is a partly sectional and enlarged elevational view of the mold opening and closing means in conjunction with the means for preventing backrinding of the molding compound or stock during a curing operation, the means for extracting a molded article from a mold, and the means for clearing lthe sprue in the sprue plate of the mold;

FIG. 5 is a sectional view taken along theA line 5-5 in FIG. 4 with the article extracting means removed;

`FIG. 6 is a sectional 'view taken along the line 6-6 in FIG, 4;

' FIG. 7 is a sectional view taken along thev line 7-7 in FIG. 3;

FIG. 8 is an end elevational view, taken from the right-hand side of FIG. 7, of the rack and pinion mechanism for the anti-backrinding means and shows this 3 mechanism in the operative position of the anti-backrinding means; l

FIG. 9 is a sectional view taken along the line 9-9 in FIG. 3;

FIG. 10 is a fragmentary sectional View taken along the line 10-10 in FIG. 7;

FIG. 11 is a sectional, enlarged det-ail view of a twoplatemold which may be incorporated in the machine according to the invention;

FIG. l2 is a fragmentary, partly sectional top plan View of a clutch mechanism for disconnecting either of the mold wheels from the drive means therefor;

FIG. 13 is a partly sectional side elevational view of the clutch mechanism shown in FIG. 12;

FIG. 14 is a sectional view taken along the line 14--14 in FIG. l2 and illustrates an arrangement for heating the molds by means of steam or other Huid;

FIG. 15 is a sectional view similar to FIG. 14 and illustrates a slip ring and brush form of electric mold heating arrangement;

FIG. 16 is a view taken along the line 16-16 in FIG. 15;

FIG. 17 s a partly sectional elevational view of a modied form of the mold opening and closing means associated with hydraulic mold clamping means;

FIGS. 18 and 19 .are partly sectional elevational views of a modified actuating arrangement for the mold opening and closing means; and

FIG. 20 is a fragmentary sectional view taken along the line 20-20 in FIG. 19.

General Organization Referring first to the drawings in general, it will be seen that the duplex molding machine according to the present invention comprises a frame A, a dual turret or mold wheel arrangement B including two sets of multiplate molds, mold opening and closing means C, molding compound feeding and injecting means D, anti-backrinding means E, mold wheel indexing means F, Vmeans G for extracting the cured articles from the molds, and sprue clearing means H. All of the -means B to H are supported on the frame A of the machine and cooperate through the intermediary of suitable control means to carry out completely automatically the various operations for each molding cyclefor each mold carried by the mold wheels. The structural characteristics of the respective parts of the machine will now be described in greater detail.

T he Frame Referring now to FIGS. 1, 2 and 13, it will be seen that the frame A of the automatic molding machine comprises four stanchions or base members 20 mounted on any rigid surface 21, such as the floor of a factory building or'room, through the intermediary of a plurality of base plates22 welded or otherwise rigidly affixed to the lowermostends of the respective stanchions. Each stanchion 20 is preferably of welded construction and substantially T-shaped in cross-section, with the center web 20a of each stanchion facing inwardly of the frame A. The stanchions 20 are arranged at the front and rear of the machine by pairs and in laterally downwardly diverging planes, and the corresponding oppositely located diverging stanchions are interconnected intermediate their ends by horizontal transverse struts 23 welded thereto at the opposite faces of the welded center webs 20a of the stanchions.

Rigidly affixed to the upper ends of the respective pairs of diverging stanchions 20, as by being welded thereto, are two cross members 24 to which are secured, as by bolts 25,` respective journals 26 and 27 for rotatably supporting the mold Wheel arrangement B (still to be described). Two vertical welded brackets or frame members 2S', to the uppermost horizontal portions 28a of which are secured, respectively, the mounting or base plates 28 for the two injection units associated with the two mold 4 wheels, are welded to the opposite ends of each of the cross members 24.

In addition, four brackets or angle members 29 are welded, respectively, to the outer faces of the stanchions 2 0 intermediate the ends of the latter, these brackets constituting the mounting and supporting means for a pair of substantially annular stationary shields or housings 30 the purpose of which will be more fully explained hereinafter. As can be seen from FIGS. 1 and 2, the front housing or shield 30 comprises a vertically extending annular plate 31 which is cut away at its uppermost sector, thus being provided With radially extending edges 32--32, and provided at its inner periphery with a horizontally extending flange 31a, and a horizontally extending substantially annular plate 33 which is welded to the vertical plate 31 adjacent the outermost periphery thereof (see FIG. 2) and is provided adjacent its own outer periphery and on its inner surface with a groove or channel 34. The plate 33 is coextensive with the plate 31 and thus terminates in respective edge planes coinciding with the edges 32-32 of the plate 31. The rear shield or housing 30, being identical with the front one, is not explicitly illustrated or described herein.

Rigidly attached to and extending upwardly from the two injection unit mounting platforms 28 (only one of which is shown) are two vertical frame members 35 the uppermost ends of which are connected by a horizontal cross member 36. Depending from the cross member 36 are two brackets or plates 37 to which are attached a pair of arcuate horizontally extending brackets 38 deiining, respectively, a pair of downwardly facing grooves or channels 39. The location of the channel brackets 38 is such that the channels 39 thereof are aligned with the channels 34 provided in the horizontally extending plates 33 of the shields or housings 30, to thereby form a substantially continuous groove or channel. Each groove or ch-annel 34-39 is substantially constant over its cntire length except at one location near the top of the machine where it deviates from its normal path, as shown at 39a in FIG. 5, along a cam element 38a rigidly attached to the associated brackets 37 and 38, for a purpose to be more fully described hereinafter.

Provided in the interior of the vertical front shield plate 31 are two substantially annular, concentrically arranged channels or conduits 40 and 41 which communicate with one another adjacent one of the edges 32 of the plate 31 via a short, radially extending bore 42 and which are in communication at their other ends with a pair of conduits 43 and 44, respectively, serving as the inlet and outlet lines for any suitable fluid heating medium, such as steam. The same arrangement is, of course, provided in the rear shield plate 31 (not shown).

The Mold Wheel Arrangement Rotatably supported by the journals 26 and 27 and extending centrally through the machine is a hollow shaft 45 which carries at spaced locations intermediate its ends a pair of mold wheels 46 and 47. As clearly shown in FIGS. 1 and 2, the mold wheel 46 comprises a hub 48 connected to the shaft 45 by means of a key 49 and having welded thereto at respective locations spaced 90 from one another circumferentially of the hub a plurality of radially extending arms 50 the outermost ends of which are connected to one another by a peripheral flange 51. A plurality of ribs 50a are Welded to the hub 48 and the inner faces of the arms 50 so as to provide extra bracing for the latter, thereby to enhance the strength and rigidity of the mold wheel 46. The mold wheel 47 which faces frontwardly of the machine, with a plurality of mold-retaining recesses 53 in each of which the bottom element of a multi-plate mold, presently to be described, is adapted to be seated.

As most clearly shown in FIGS. 2, 3 and 4, according to this embodiment of the invention each mold is composed of three mold elements 54, 55 and 56, of which the element 54 constitutes the sprue or top member of the mold, the element 55 the cavity member into which the molding compound is injected, and the element 56 the back-up or bottom member of the mold. It will be understood that the terms top and bottom are employed herein in their conventional senses (despite the fact that the mold wheel rotates in a Vertical plane) to designate the mold elements or members which, respectively, serve to admit the molding compound into the mold cavity and to close that end of the mold cavity opposite to the point of entry of the molding compound. In a manner which will be more fully explained hereinafter in connection with the description of the mold opening and closing means C, the mold elements 54 and 55 of each mold are arranged for linear parallel movement toward and away from the associated mold element 56, each top mold element 54 being additionally arranged for angular movement relative to its associated mold cavity member 55.

The mold ring 52 is further provided, on that surface thereof which faces inwardly (rearwardly) of the machine With a pair of substantially concentric channels or conduits 57 and 58 extending circumferentially over the mold ring at respective radial locations opposite and corresponding to the radially innermost and outermost edges of the mold-retaining recesses 53. Fixedly carried by and extending axially through the mold wheel-supporting and driving shaft 45 for rotation therewith is a steam inlet pipe 59l the outer end of which is connected to a rotary coupling 60 stationarily arranged on the machine frame and adapted to be connected to a source of high pressure steam (not shown). The inner end of the inlet pipe f is connected to a pipe section 6l extending radially from the shaft 45 and connected in turn via a perpendicular pipe section `62 to a 4small pipe tting 63 aflxed to and extending through a bore in the mold wheel ange 51 into communication with a relatively short radial passageway l64 formed in the mold ring 52. The passageway 64 communicates at its other end with one end of the radially inner steam channel 57. The other end of the channel 57 (which may be located adjacent the aforesaid one end thereof) communicates via another short radial passageway (in a manner similar to the communication established by the passageway 42 between the the steam channels 40` and 41 of the shield 30) with one end of the radially outer channel or conduit 58 the other end of which communicates via a radial passageway 65 and another pipe fitting 65a extending through the mold wheel `flange 5l with a pipe 65 aliixed thereto at one end and extending in a direction substantially parallel to the axis of the shaft 45 to the mold wheel flange 51' of the other mold wheel 47.

The mold wheel 47 carries on its flange 5l a mold ring 52 identical in all respects with the mold ring 52 of the mold wheel 46, and thus neither the mold-retaining recesses nor the steam conduits thereof corresponding to the recesses 53 and conduits 57-58 of the mold ring 52 are explicitlyr described or illustrated herein. The pipe `66, therefore, communicates at its other end with one of the circumferential steam channels in the mold ring 52', which steam channel communicates with the other steam channel which in turn communicates with a short pipe section 67 connected to the mold Wheel flange 5l. The pipe section 67 is connected via a pipe section 68 extending parallel to the shaft 45, and via a pipe section 69 extending radially of and into the shaft, with a steam outlet pipe 70 tixedly carried by and exlar to the coupling 60 to a steam exhaust line (not i shown).

From the foregoing -it will be understood that steam under high pressure may be admitted through the coupling 60 into the inlet pipe 59 and thence into the channels 57 and 58 of the mold rings 52 and 52 even during rotation of the shaft 45 and the mold wheels 46 and 47, for the purpose of heating the respective sets of molds carried thereby. The steam, after coursing through both the mold rings, leaves the mold ring 52' and is exhausted in any suitable manner via the outlet conduit 70 for disposal or recycling, as desired.

Referring now particularly to FIGS. 3 and 4, it will be seen that the mold ring 52 is further provided at its radially outermost edge and on the side facing frontwardly of the machine frame A with a peripheral ridge or flange 7l which extends radially from the ring to an extent sufficient to permit engagement thereof With the associated downwardly depending bracket 37 affixed to the cross member 36y of the frame members 3S. As will presently become clear, the function of the flange 71 when in engagement with the bracket 37 is to provide means for taking up the lateral forces exerted on the mold ring by the injection unit of the molding compound feeding and injecting means D during an injection operation.

The mold ring 52 is further provided at a plurality of locations, corresponding in number to the number of mold-retaining recesses 53, with horizontally extending brackets 72 welded, for example, to the outer face of the flange or ridge 71 and provided at their free ends with respective fingers or lugs 73 extending radially inwardly of the mold wheel 46. The mold ring 52 is still further provided, adjacent each recess 53 and at locations diagonally opposite the brackets 72, with similar brackets 74 at the free ends of which are arranged fingers or lugs 75 (see FIG. 5) extending radially outwardly of the mold Wheel 46. The function of these brackets 72-73 and 74-75 will be more fully explained hereinafter in connection with the description of the mold opening and closing means C.

In a similar manner, as clearly shown in FIG. 2, the mold ring 52, is provided with a peripheral ridge or llange 71', with a plurality of brackets 72'-73 and with a plurality of other brackets (not shown) diagonally opposed to these, which structural elements perform the same functions as the ridge or ange 71 and thel brackets 72-73 and 74-75 on the mold ring 52.

The Mola' Opening and Closing Means Referring again to FIGS. 3 and 4, it will be remembered that the recesses 53 in the mol-d ring 52 (and also in the mold ring 52') were identified hereinbefore as mold-retaining recesses. Strictly speaking, however, this designation is only partly accurate inasmuch as only the bottom elements 56 of the various molds are seated and retained in the respective recesses 53. The intermediate or cavity elements 55 of the various molds are mounted and retained in respective bores or openings 76 of a plurality of carrier plates 77 arranged in side by side relationship and spaced from one another circumferentially of the associated mold rings, while the top or sprue elements 54 of the various molds are mounted and retained in respective shouldered bores 78 of Va plurality of carrier plates 79 also arranged in side by side relationship and spaced from one another circumferentially of the associated mold rings. IFor a purpose which will presently become apparent, the bottom mold elements 56 are suflciently large to project slightly out of their recesses '53, while the cavity elements 55 are suiciently large to project slightly out of their recesses 76.

As hereinbefo-re indicated, each of the rnold rings SZ and 52' is provided with a great number of recesses 53, for example forty in number, to accommodate an equal number of molds, which permits attainment of much greater production rates than has been possible heretofore. For the sake of clarity, only a few of these molds are shown in FIG. l. Moreover, each of the molds has associated therewith an individual mold opening and closing arrangement, all of which are identical in all respects. For they purpose of a description of the mold opening and closing means C, therefore, only one arrangement thereof in association with a single mold associated with the mold wheel 46 and the mold ring 52 thereof will be specically described at this time.

Turning now to FIGS. 3 to 6, it will be seen that the intermediate mold carrier plate 77, into which the cavity element or insert SS has been fitted, is provided in its lowermost (radially innermost) edge with a rectangular recess 80 and in its uppermost (radially outermost) edge region with a shouldered bore or opening 81 in which is retained a split bushing 82. The recess 80 and the bushing 82 are adapted to accommodate correspondingly shaped portions of a pair of operating rods 83 and 84, respectively, both of which are disposed at right angles to the plane of the carrier plate 77 and extend slidably through a pair of bores 85 and 86 provided in the mold ring 52 at radially spaced locations adjacent the innermost and outermost edges of the mold-retaining recess 53, the bores 85 and 86 extending from the front face of the mold ring 52 through a pair of projections 87 and 88 integral with the mold ring and facing inwardly of the machine frame A (to the right in FIGS. 3 and 4).

As clearly shown in FIG. 6, the front end 83:1 of the mold operating rod 83 is milled flat on its opposite sides, thereby providing a pair of shoulders 83b on the rod 83 adapted to engage the rear surface of the intermediate carrier plate 77 at the opposite sides of the recess 80 thereof. The fiattened rod portion 83a extends forwardly from the shoulders 83a of the rod 83 to a point beyond the front surface of the carrier plate 77 and is provided adjacent its foremost end with a transverse bore 83C.

Referring to FIG. 3 in particular, it will be seen that the second mold operating rod 84 is shaped in the form of a hollow tube the opposite ends of which are internally threaded, as shown at 89 and 90, respectively. Screwed into the end 89 is a substantially tubular fitting or sleeve element 91 provided with an annular shoulder-forming fiange 92 intermediate its ends, the portion 93 of the element 91 located exteriorly of the tube 84 being dimensione'd to be slidably received in the split bushing 82 mounted in the bore 81 of the intermediate carrier plate 77. The axial length of the section 93 of the element 91 is greater than the -axial thickness of the bushing S2. The element or fitting 91 is further provided at the front end of the section 93 thereof with a section 94 of reduced diameter, thereby forming an annular shoulder 95 facing forwardly (outwardly) of the machine frame A. At its front end, the fitting section 94 is provided with an enlarged, elongated head 96 which is milled flat on its opposite longer faces. The entire fitting 91, including all of the sections and the head thereof, is provided with an axial bore 91:1 the function of which is to provide a passageway for an element still to lhe described and constituting a part of the anti-backrinding means E.

In contradistinction to the first mold operating rod 83, which is adapted to execute only linear reciprocal sliding movement through the bore 85 in the mold ring 52, the rod 84 is required to perform both linear and angular or rotary reciprocal movements within the bore 86 of the mold ring. To this end (FIG. 4), there is provided in the rod or-tube 84 intermediate the ends thereof a double-faced or sided cam groove 97 into which extends a small projection 92a of a guide screw or bolt 93 fixedly positioned on the mold ring 52. The cam -groove 97 is provided with linear end sections and an angled or curved center section, whereby the rod 34 will be rotated while being moved axially through the bore 86, but only for a preselected portion of this axial movement.

Screwed into the end of the rod or tube 84 (FIG. 3) is a second substantially tubular fitting or sleeve element 99 provided intermediate its ends with a shoulderforming annular fiange 100 from which extends a section 101, the latter in turn being connected with a section 102 of reduced diameter which is externally threaded at its outermost end, as shown at 102:1. Slidably mounted on the outermost end of the intermediate fitting section 101 is a multi-section housing 103 the sections 103m and 103b of which define an inner chamber 104, and the section 103C of which constitutes a part of the antibackrinding means E. The housing sections are secured to one another by bolts 103:1 (see FIG. 7). As shown in FIG. 3, the fitting section 102 is disposed entirely within the chamber 104, while the fitting section 101 extends through a bore 103e at one end of the housing. Surrounding the section 101 exteriorly of the housing 103 and intermediate the latter and the shoulder-forming flange 100 is a thrust bearing 105 the axial dimension of which is such that there is normally a slight clearance between the front face of the bearing and the rear face -or shoulder of theI yflange 100. The importance of this feature of the invention will be more fully explained hereinafter.

Fixedly mounted on the fitting section 102 within the housing 103 is a cylindrical sleeve 106 which is provided with an outer annular fiange 106:1 at one end and is internally threaded at the same end so as to enable it to be lscrewed onto the threaded end 102e of the fitting section 102. Surrounding the sleeve and abutting at one face against the fiange 106:1 is a thrust bearing 107 the other face of which is engaged by one end of an extremely strong spring 108, capable of exerting a thrust of about 2,000 pounds, the other end of which abuts against the end wall of the housing 103 about the bore 103e. A nut 106b screwed onto the end of the fitting section 102 locks the sleeve 106 in position. As in the case of the fitting 91, the fitting 99 is provided with an axial bore 99:1 adapted to accommodate the aforesaid and still to be described element of the anti-backrinding mechanism E.

The housing section 103:1 is provided with a downwardly depending portion or yoke 109 provided with a transverse bore 110. The first mold operating rod 83 is provided with a portion 83d of reduced diameter extending from the rear or innermost end of the rod 83. The rod portion 83d extends slidably through the bore 110 and is constrained to linear reciprocal movement therein by a key and groove arrangement 111. The rod portion 83d is externally threaded adjacent its outermost end and carries a sleeve 112 provided with an annular fiange 113, a compression spring 114 surrounding the sleeve 112 and being interposed between the flange 113 and the opposite face of the depending yoke 109. The sleeve is retained in position on the rod portion 83d by any suitable lock nut or Washer structure 115.

The yoke 109 is provided with a pair of projections 116 in which is retained a pivot pin 117 the axis of which extends at right angles to the axes of the mold operating rods 83 and 84. Connected to the pivot pin 117 at axially spaced locations thereon are two toggle links or arms 118 which are connected at their other ends to a pivot pin 119 retained in a pair of projections 120 of a toggle 121, the latter in turn being mounted for angular movement about apivot pin 122 mounted in the projections 87 and SS of the mold ring 52. Extending upwardly from the toggle 121 is an arm 123 the outermost end of which is connected to one end of a bell crank lever 124. The bell crank lever 124 is pivotally mounted on the mold ring projection 88 by means of a pivot bolt 125 disposed coaxially with the pivot pin 122 of the toggle 121. At its other end, the bell crank lever 124 carries a cam or follower roller 126, and the arrangement is such that the 9 roller 126 is adapted to extend into and ride along the channel 34-39 defined by the horizontally extending portion 33 of the front mold wheel shield 30 and the horizontally extending bracket 38 affixed to the frame A through the intermediary of the vertical bracket 37.

Referring now particularly to FIGS. and 6, it will be seen that the mold carrier plate 79, in the shouldered recess 78 of which the top or sprue element 54 of the mold is mounted, is provided at one end with a pair of spaced, parallel projections 127 and 128 in which are formed respective transverse bores 1270i and 128er. The flattened end portion 83a of the rod 83 extends into the space between the arms 127 and 128, the bore 83C of the rod portion 83a being axially aligned with the bores 127a and 128a. Rotatably arranged within the bore 83e of the mold operating rod portion 83a is a cross pin 129 one end of which extends through the bore 127g and the other end of which extends through the bore 128a. Fixedly connected to the cross pin 129 at the end thereof projecting from the bore 127er is a pinion or spur gear 130. The other end of the cross pin 129 is connected to the plate 79 by means of a key and groove arrangement 131 within the contines of the bore 128e, so as to inhibit relative rotation between the plate and the cross pin. The latter may, in addition, be tixedly retained within the bores 127a-128a. by means of any suitable lock washer or nut means 132.

The carrier plate 79, adjacent the end thereof remote from the arms 127 and 128, is provided with a rectangular slot or cut-out 133 extending longitudinally of the plate and substantially centrally thereof, the innermost end of the slot 133 being disposed somewhat short of the peripheral boundary of the mold element-holding recess 78. The face of the plate 79 which in the closed position of the mold is directed away from the mold ring 52 and the intermediate carrier plate 77 is further provided with a milled out circula-r recess 134. The width of the slot 133 is such as to permit easy passage of the mold operating rod head 96 therethrough when the longitudinal dimension of the latter is disposed parallel to the longitudinal dimension of the slot, and the diameter of the recess 134 is such as to permit rotation of the head 96 therein. The purpose and function of this arrangement will become clear presently.

The mold ring 52 is further provided with a bore 135 disposed laterally of the bore 85 and parallel to the latter, the bore 135 extending from the front face of the mold ring to the rear face thereof. Slidably arranged within the bore 135 is a bar 136 one of the ends of which extends forwardly from the mold ring and is provided with teeth 137 defining a rack, the teeth 137 meshing with the teeth of the gear or pinion 130. Rigidly connected at one end to the other end of the bar 136 and projecting from the latter reanwardly of the mold ring is a pusher rod 138 the other end of which extends Slidably into and through a bore 139* provided in the lowe-rmost end region of the yoke 109 (see also FIGS. 3 and 4). Fixedly mounted on the pusher rod 138 intermediate the ends thereof is a stop member 140l (the stop member may, of course, be adjustably fixed on the pusher rod). Surrounding the pusher rod between one face of the stop member 140 and the adjacent face of the yoke 189 is arranged a compression spring 141.

The operation of the mold opening yand closing means C will thus be seen to be as follows:

When, as illustrated in FIG. 3, both the rods 83 and 84 are in their most retracted positions, as a result of the corresponding positioning of the yoke 109 and toggle 121 under the inuence of the cam roller 126 which is located at an undeilected portion of the cam track or channel 39 spaced from the deflecting portion 39a thereof, the head 95 of the mold operating rod 84 is disposed at the forward face of the top carrier plate 79 and oriented crosswise to the slot 133. The spring 188 in the housing 103 thus exerts a powerful pull on the rod 84 due to the provision of the slight clearance between the shoulder 100 and the thrust bearing 105, which pull is transmitted by the rod 84 and the head 96 thereof to the top carrier plate 79 adjacent one edge of the latter. Concurrently with the foregoing, the spring 114 exerts `a similar pull on the mold operating rod 83 and, through the same and the cross pin 129, on the other edge of the top carrier plate 79, whereby the latter is drawn uniformly toward the intermediate carrier plate 77. Inasmuch as the base or bottom rnold insert 56 is shaped so as to project slightly beyond the connes of the recess 53 in the mold ring 52, while the cavity insert 55 is shaped to project slightly beyond the confines of the carrier plate 77, there is provided a slight clearance between the adjacent surfaces of the mold ring 52 and the intermediate carrier plate 77, as well as between the adjacent surfaces of the intermediate and top carrier plates 77 and '79. Consequently, a thorough and uniform clamping of the mold lands against one another is affected in such a manner as 'will tend to substantially inhibit the formation of ilash therebetween.

At this point, with the mold operating rod head 96 turned crosswise of the slot 133, the guide bolt 98 is located in the forwardmost linear end section of the cam slot 97, which portion of the latter extends parallel to the axis of the mold operating rod 84. For the purpose of opening the mold, the cam roller 126 reaches the offset portion 39a of the cam track or channel 39, whereupon the bell crank lever 124 is pivoted about its axis 125 in such a manner as to swing the toggle 121 about the pivot pin 122 thereof in the direction required to cause the yoke 189 to be pulled forwardly, i.e., from right to left as seen in FIG. 3. Accordingly, the rod 83 will be moved to the left due to the engagement between the yoke 109 and the shoulder formed between the main portion of this rod and the reduced diameter portion 83d thereof, While at the same time the rod 84 will be moved to the left through the intermediary of the housing 103 and the thrust bearing 105, the latter of which now bears against the shoulderforming flange 100 of the element 99 affixed to the rod 84.

During the initial part of this movement of the rods 83 and 84, the projection 98a of the guide bolt 98 rides along the aforesaid relatively short forwardrnost linear end section of the cam groove 97. Thus, the rod 84 is moved linearly only for a short distance and is not rotated about its axis and, consequently, the radially outermost end region of the top carrier plate 79 is moved away from the intermediate carrier plate 77 with a straight, parallel motion through the intermediary of the shoulder formed on the element 91 aflixed to the rod 84. At the same time, the movement of the yoke 109 is transmitted through the spring 141 and the stop 140 to the pusher rod 138 and thence to the rack bar 136, the latter thereby being moved jointly with the rod 83. Accordingly, there is no relative movement between the rack bar 136 and the pinion 130, as a result of which the other or radially innermost edge of the top carrier plate 79 is also moved away from the intermediate carrier plate 77 with a straight, parallel motion. Viewed as a unit, therefore, the top carrier plate 79 is first moved parallel to the intermediate carrier plate 77 while the latter remains stationary.

After the rods 83 and 84 have been moved through a predetermined distance suicient to extract the sprue element 54 completely from the confines of the cavity element 55, the shoulders 83b on the rod 83 contact the intermediate carrier plate 7 7, while the shoulder formed bythe ange 92 of the fitting 91 engages the split bushing 82, it being understood, of course, that the shoulders 8317 and 92 are located in the same vertical plane. The intermediate carrier plate is thus moved away from the mold ring 52 with a straight, parallel motion so as to separate the cavity element 55 (and, of course, any molded article retained therein) from the bottom mold element 56. The parallel motions of the top and intermediate carrier plates are important features of the present invention, since they bring about the highly desirable result of considerably prolonging the useful life of the mold by substantially eliminating uneven wear of the mold elements.

At this time, the projection 98a of the guide bolt 98 enters the angled or curved center section of the cam groove or slot 97 in the rod 84, as a result of which further axial movement of the latter is accompanied by a rotation thereof in such a manner as to bring the head 96 into alignment with the slot 133 in the top carrier plate 79. As soon as this has taken place, the stop 14) on the rack pusher rod 13S reaches the rear face of the mold ring 52 with the consequence that further forward movement of the rack bar 136 is arrested. It will, therefore, be readily understood that as forward movement of the rod 83 continues, the meshing of the teeth 137 of the rack bar 136 with the teeth of the pinion 130 causes the latter to be rotated in a counterclockwise direction as seen in FIG. 3, with the result that the cross pin 129 and therewith the top carrier plate 79 are likewise angularly moved to bring the latter into the horizontal position shown in FIGS. 4, and 6, such angular movement of the plate 79 being permitted by virtue of the fact that the head 96 of the rod 84 was previously moved into alignment with the slot 133 and is now no longer being rotated due to the engagement of the guide bolt projection 98a with the rearwardmost linear portion of the cam groove 97. At this point, the intermediate carrier plate 77 is engaged by the lingers 73 and 75 of the stop brackets 72 and 74, respectively, and any further forward movement of the intermediate carrier plate is inhibited. It will be understood that the respective brackets and their associated lugs or lingers may be replaced by headed bolts, generally referred to by the term stripper bolts, which extend slidably through suitable openings provided in the intermediate carrier plate of the molds. The purpose of this arrangement will be more fully described hereinafter in connection with the description of the article extracting or ejecting means G.

When the cam rollers 126 is returned to its normal position in an undeilected portion of the channel 39, the foregoing movements of the various carrier plates and their operating means are repeated in reverse. First, the toggle 121 is swung so as to move the yoke 109 to the right as seen in FIG. 3, which movement is transmitted to the mold operating rods 83 and 84 through the springs 114 and 108, respectively. At the beginning, of course, both the rods move linearly only, and since the spring 141 is still under compression, the mold operating rod 83 moves while the pusher rod 138 and rack bar 136 remain stationary. The pinion 130 is thus rotated in a clockwise direction as seen in FIG. 3, whereby the top carrier plate 79 is swung upwardly past the head 96 of the mold operating rod 84. Thereafter, as soon as the yoke 109 has moved suiciently far to permit the stop 149 to be separated from the rear face of the mold ring 52, which takes place upon complete relaxation of the compression of the spring 141, relative movement between the pinion 13) and the rack bar 136-137 ceases so as to bring about straight, parallel movement of the carrier plate 79 toward the carrier plate 77 and subsequent straight, parallel movement of the latter toward the mold ring 52. Concurrently, the return movement of the guide bolt projection 98a along the curved center section of the earn groove or slot 97 causes the head 96 to be rotated back into its initial position crosswise of the slot 133. At the end, the springs 108 and 114 will again be operable to apply the needed clamping pressures to the various carrier plates and the mold elements thereof, due to the presence of the hereinbefore described slight clearance between the thrust bearing 105 and the shoulder-forming flange 190 of the fitting 99, this clearance simultaneously enabling the machine to compensate for normally encountered tolerance variations in the dimensions of the various mold inserts or elements.

The machine according to the present invention is so constructed that molding compound is injected into each mold at only one station along the periphery of each mold wheel. Again, only one of the compound feeding and injecting arrangements will now be described in detail, inasmuch as the other one is in all respects identical therewith.

As previously set forth herein, the molding compound feeding and injecting means D is supported on a mounting or base plate 28 aixed to the uppermost horizontal portion 28a of the vertical frame member 28 at the space 'between the edges 32 of the mold wheel shield 30. Referring now in particular to FIGS. 1, 2, 3 and 9, it will be seen that a double-acting hydraulic motor cylinder 142 provided with pressure iiuid lines 143 and 144 is rigidly mounted on the base plate 28', one cross-head 142:1 of the cylinder being secured, as by bolts or the like, to the frame member 35 affixed to the base plate 28. Reciprocally arranged within the cylinder 142 is a piston (not shown) provided with a piston rod 145 projecting out of the cylinder through any suitable stuffing box 146 and inwardly of the machine frame A through an opening in the frame member 35, the front end of the piston rod 145 carrying an injection piston 147 which may be secured to the piston rod in any suitable manner, as by being screwed thereto through the intermediary of internal threads on the injection piston and corresponding external threads on the piston rod 145. The injection piston 147 extends into an injection cylinder 148 which is mounted for reciprocal axial sliding movement in and through an annular support 149 rigidly afiixed to the mounting plate 28 by bolts 150.

The cylinder 148 is provided at that end thereof remote from the point of entry of the injection piston 147 with an annular inturned flange 148a the inner peripheral edge of which deiines an opening 148b through which the molding compound is to be injected into the molds. Aflixed to the injection cylinder 148 by means of screws or bolts 151 and extending across the opening 148b is a relatively thin, flexible, metallic plate 152 in which is provided an aperture 152:1. The plate 152 thus constitutes a sprue plate for the injection cylinder, and its sprue opening 152a is so positioned as to register with the sprue in the top element 54 of the mold. Although only one sprue opening is shown, the number and distribution of such openings across the plate 152 will always correspond exactly to the number and distribution of the sprues in the top mold element 54. The plate 152 is flexible to enable the same to adapt itself to and to lie flush against the entire free face of the mold element 54 under the pressure applied to the molding compound in the injection cylinder 148 during the injection stroke of the piston 147, whereby the pressure will be evenly distributed over the area of the mold while any escape of molding compound between the sprue plate 152 and the mold element 54 will be prevented. In effect, therefore, even though the injection cylinder bottom is covered by the sprue plate 152, the injection operations carried out by the machine according to the present invention are still of the bottomless cylinder type, the advantages of which are well known, and the disadvantages of which are eliminated by the present invention.

At its other end, the cylinder 148 is provided with an annular outwardly directed iiange 153 to which are aiixed in any suitable manner and at a plurality of equi-angularly spaced peripheral locations, 'for example six in number, a plurality of headed shoulder bolts 154 and a plurality of guide pins 155 alternating with the shoulder bolts 154. As clearly shown in FIG. 3, the support 149 is provided with a plurality of recesses 149a into which the shoulder bolts 154 extend, the heads 154:1 of the shoulder bolts being engageable with the bottoms of the respective recesses 149a to limit the extent of sliding movement of Ythe injection cylinder outwardly of the frame A during retraction of the cylinder from the mold. The support 149 is further provided with a plurality of recesses 149b, the guide pins 155 extending through the recesses 149i), respectively, and being surrounded by compressions springs 156 each bearing at one end against the injection cylinder flange 153 and at the other end against the bottom of the associated recess 14911. The 'function of the springs t-hus is to effect a refractive movement of the injection cylinder 148 through the support 149 to the extent permitted by the shoulder bolts 154.

Rigidly mounted on the base plate 28 intermediate the frame member 35 and the support 149 is a frame member 157 at the center of which is provided an upwardly concave portion 158 which defines an additional sliding support surface for the injection piston 147 and also a receiving or starting place for the molding compound to -be injected into the mold by the piston 147. Positioned above the frame member 157 and terminating in a downwardly concave arcuate edge plane 159 is a feeding chute 160 of substantially rectangular cross-section defined by a front wall plate 160a, a rear wall plate 160]), and side wall plates 160e and 160d welded together at their respective edges and rigidly affixed to the cross member 36 interconnecting the members 35, preferably by means of a welded angle member 161. The chute 160 provides a path of movement for the molding compound into the starting position thereof in which it can be picked up by the injection piston, as more fully explained hereinafter.-

Fixedly connected with the injection piston 147 and its piston rod 145 is a pin 162 which projects laterally from the injection piston into engagement with a first or actuating slide 163 arranged for linear reciprocal movement in a horizontal slideway 164 of the frame member 157, the slide 163 being provided with a recess 16311 in which the hea-d of the pin or screw 162 is received. The slide 163 is provided with an upwardly extending arm 165 at the uppermost end o-f which is pivotally supported by means of a pivot pin 165a a pawl or latch member 166 integral with a cam 167, a torsion spring 168 or the like being associated with the pivot pin 165a in such a manner as to bias the pawl downwardly (in a clockwise direction as seen in FIG. 3). The pawl 166, as canv be seen from FIG. 9, is located adjacent the outer surface of the side wall plate 160C of the chute 160.

Reciprocally mounted in a suitable horizontal slideway or guide structure 169 afiixed to and extending between the frame member 35 and the front wall plate 169e vof the chute is a second slide 170 provided at that end thereof facing toward the chute with a pair of spaced, parallel fingers 171 and 172 and with a pair of side members 173 and 174 located adjacent and spaced from the remote side l edges of the fingers 171 and 172, respectively. At a location aligned with the track or path of movement of the .slide 170, as defined by the slideway 169, the front wall plate 160a of the chute is provided with a transverse opening adapted to permit entry of the fingers 171 and 172 into the chute. The fingers of the slide 170I are so spaced from one another as to be located immediately adjacent the respective inner surfaces of the side wall plates 160e and 160d of the chute when the slide is moved to position the fingers within the chute, and the `spaces between the fingers 171 and 172 and their associated side members 173 and 174 are `sufficiently wide to receive the side wall plates 160C and 160d, respectively, when the slide is moved into the position ilustrated in FIG. 3. The arrangement is such that the lowermost edge of the pawl 166 bears against the upper edge 4of the side member 173 of the slide 170 at ail times under the force of the spring 168.

At its other end, the slide 170 is provided with a guide rod 175 extending toward the frame member 35 which is provided with a bore 176 adapted to receive the guide rod 175 when the slide 17)I is moved lso as to withdraw the fingers 171 and 172 from the chute 168. interposed between the slide 17) and the frame member 35 and sur- 14 rounding the guide rod is a compression spring 177 the function of which is to bias the slide 170 toward the chute 166.

Pivotally lmounted at one end by means of a pin 178 on a block 179 attached to the frame of the machine is a lever 180 the lower edge of which normally rests on the upper edge of the cam 167 connected with the pawl 166. The lever 189 is biased downwardly (in a counterclockwise direction as seen in FIG. 3) by a spring 181 bearing against the upper edge of the lever adjacent the free end thereof and mounted on the frame of the machine, a stop 182 being provided to limit upward movement of the lever against the force of the spring 181. The lever 180 is adapted to rock the cam 167 ina manner and for a purpose which will be more fully explained hereinafter.

Positioned above the slideway or guide structure 169 is a similarly constructed horizontal slideway or guide `s tructure 183 one end of which is rigidly attached to the upright frame member 35 and the other end of which is attached to the front wall plate 16011 of the chute 160, the front wall plate 169a being provided with a transverse opening 184 aligned with the -space between the upper and lower members of the guide structure 183. Slidably disposed within the latter for reciprocal movement therealong is a third slide 185 which is provided at that end thereof facing the chute 160 with a pair of spaced parallel fingers 186 and 187 and with a pair of side members 188 and 189 spaced from and parallel to the remote sides of the fingers 186 and 187, respectively. The fingers 186 and 187 are adapted to enter the chute 160 through the opening 184 and are spaced from one another in such a manner as to be located closely adjacent the chute side wall plates 160e and 160d upon movement of the slide 185 toward the chute, the spaces between the fingers 186 and. 187 and their associated side members 188 and 189 being sufficiently wide to accommodate the aforesaid chute side wall plates. For ease of reference, the slide 17@ will hereinafter be referred toas the lower slide and the slide 185 as the upper slide.

Fixedly attached to a block 190a mounted on the machine frame laterally of and intermediate the guide structures 169 and 183 is a pivot bolt or like element 190 on which is rockably mounted a two-armed link or transmission lever 191. The lever 191 is articulated at its upper end by means of a pin 191g to the side member 189 of the upper slide 185, and at its lower end by means of a pin 19111 to the side member 174 of the lower slide 170. The arrangement is such that when the lower side 170 is in its advanced position with the fingers 171 and 172 extending across the interior of the chute 160, the upper slide 185 is in its retracted position, and vice versa. Referring in particular to FGS. l and 2, it will be seen that the cross frame member 36 further supports a housing 192 comprising parallel, spaced front and rear wall plates 193 and 194 connected at their corresponding opposite edges by side wall plate (not shown). Rotatably journaled in the housing plates 193 and 194 is an axle or shaft one end of which projects from the housing 192 through the rear wall plate 194 thereof. Fixedly mounted on the shaft 195 immediately adjacent the outer surface of the rear wall plate 194 is -a ratchet wheel 196 the teeth of which face in a clockwise direction as seen in FIG. 1. Loosely mounted on the shaft 195 adjacent the outer surface of the ratchet wheel 196 is a two-armed or bell crank lever 197 one arm of which carries, by means of a pivot pin 198 located -at one end thereof, a dog or pawl member 199 facing in a counterclockwise direction, as seen in FIG. 1, suitable biasing means (not shown) being provided on the lever 197 or the pivot pin 198 to continually urge the pawl 199 into engagement with the outer surface of the ratchet wheel 196.

`Fixedly mounted atop the housing 192 is a cylinder 260 of a double-acting pneumaticv motor, the cylinder 280 being provided with pressure uid lines 20011 and 20Gb and With a piston (not shown) reciprocal in the cylinder. Connected to this piston and projecting downwardly therefrom through an opening 192e in the top of the housing 192 is a piston rod 201 to the lowermost end of which is connected a shearing blade or cutting member 202 which fits slidably into the space between the front and rear wall plates 193 and 194- of the housing 192. Also connected to the piston rod 201 above the blade 202 and extending out of the housing 192 through a suitable recess provided in the rear wall plate 194- is a transverse arm 203 to the outermost end of which is articulated one end of a link 204, the other end of the link 204 being articulated to the free end of the second arm of the bell crank lever 197. The shaft 195 further supports, at a location intermediate the front and rear wall plates 193 and 194 of the housing 192, a wheel member 205 provided in its periphery with a plurality of equi-angularly spaced pockets or recesses 206 each adapted to receive a quantity of the molding compound from a source of the latter, as will be described shortly. The wheel 205 will hereinafter be referred to as a transfer or feeding wheel for the molding compound, and the arrangement is such that in any given position of the transfer wheel 205 one pocket 206 thereof, to wit the uppermost one, is in vertical alignment and communication with the interior of the housing 192 defining the path of movement of the blade 202, while the pocket 206 located diametrically opposite to the first-named pocket is in vertical alignment and communication with the uppermost or inlet end of the chute 160.

Rigidly attached to the front wall plate 193 of the housing 192 and extending forwardly of the machine frame A is a horizontal platform or bracket 207 on which is rigidly mounted ya cylinder 208 of a doubleacting pneumatic motor, the cylinder 208 being provided with pressure iiuid lines 208a and 208b and with a piston (not shown) from which extends a piston rod 209. The piston rod carries at its free end a frame 210 which is provided with an aperature 211 adapted to define a passageway for the molding compound 212 which may, for example, be shaped in the form of a cylindrical rod adapted to be fed longitudinally from a rotating table (not shown) where it is initially placed in coil form. Rockably mounted on the frame 210 is a plurality of gripping elements 213 each of which is biased in the direction of the axis of the aperture 211 by a leaf spring or like element 214, each of the gripping elements 213 being preferably provided with at least one sharp edge capable of penetrating the surface of the rod of molding compound 212. In alignment with the aperature 211, there is provided in the front wall plate 193 of the housing 192 an aperature 193a, whereby the rod 212 of molding compound can enter into the housing 192. As will be readily understood from FIGS. 2, 3 -and 9, that portion of the molding compound or stock 212 which is within the housing 192 is in position to be sheared off from the remainder of the stock into biscuit-shaped slices or pieces 212e, 212/J, 212e, 212d, etc. by the blade or cutting element 202 upon lowering of the latter.

The operation of the molding compound feeding and injecting means D will be readily apparent from the foregoing and may be briefly summarized as follows:

When the piston of the stock feed motor cylinder 208 is advanced upon admission of pressure tiuid through the line 208b, after a portion of the molding compound rod 212 has been inserted through the aperture 211, the sharp edges of the gripping member 213 are pressed into the peripheral surface of the rod 212 and thus entrain the latter into movement with the piston rod 209 until the leading end of the rod 212 is positioned within the confines of the housing 192 and against the inner surface of the rear wall plate 194 thereof. The shearing motor is then actuated by admission of pressure iiuid into the cylinder 200 through the line 200!) to advance the piston thereof and thus to lower the piston rod 201 and the blade or cutting element 202. When the lowermost edge of the blade contacts the portion of the molding compound rod 212 extending across the interior of the housing 192, said portion is sheared off from the remainder of the rod and dropped into the uppermost chamber or pocket 206 of the transfer wheel 205, the latter during this time remaining stationary due to the fact that the pawl 199 carried by the bell crank lever 196 which is freely rotatable on the shaft 195 merely slides over the outer or back faces of the teeth of the ratchet wheel 196.

The feed motor is now reversed by admission of pressure fluid into the cylinder 208 through the line 208a to retract the piston rod 209 and the frame 210, as a result of which the sharp edges of the gripping members 213 are drawn out of the rod 212 so as to permit sliding movement of the gripping members along the rod 212v without any concurrent retraction of the latter from the entrance opening 193a of the housing 192. Upon concurrent admission of pressure fluid into the shearing motor cylinder 200 through the line 200a, the blade 202 is raised together with the link 204. The upward movement of the link 204 rocks the bell crank lever 197 about the axis of the shaft 195, which causes the pawl 199 to engage one of the inside or front faces of the ratchet teeth on the ratchet wheel 196 so as to rotate the latter together with the shaft 195 through a predetermined angle in the direction of the brokenline arrow in FIG. 1. The wheel 205 is thus indexed through an angle corresponding to the distance between two of the pockets 206, which places the pocket 206 containing the just formed biscuit of molding compound in a slanted position relative to the vertical and brings the next empty pocket 206 into its biscuit-receiving position below the blade 202, while at the same time a pocket previously filled with a molding compound biscuit is brought into vertical alignment with the chute 160, whereby the last-named biscuit can drop into the chute and downwardly therethrough toward the injection unit. At any given time, of course, three of the pockets 206 of the transfer wheel 205 are filled with molding compound biscuits and three are empty, having discharged such biscuits into the chute 160.

When the injection piston 147 is retracted from the injection cylinder 148 by admission of hydraulic fluid into the cylinder 142 via the line 144, the pin 162 projecting from the side of the piston causes the slide 163 and its upwardly extending arrn 165 to be moved toward the upright frame member 35. If the injection piston was previously advanced beyond a certain point in the cylinder 148, the hooked end of the latch member or pawl 166 will have dropped over the free edge of the side member 173 of the lower slide 170, as a result of which the retractive movement of the injection piston, through the intermediary of the pin 162 and slide 163, causes the slide 170 to be retracted against the force of the spring 177. Concurrently with the thus accomplished withdrawing of the fingers 171 and 172 of the lower slide 170 from thel chute 160, the advancing of the upper slide will cause the ngers 186 and 187 thereof to be positioned across the chute so as to support the molding compound biscuit 212b and any others located thereabove and to prevent the same from falling downwardly through the chute. At the same time, as soon as the slide 170 has been fully retracted, the biscuit 212:1 will be permitted to fall downwardly onto the arcuate supporting surface 158 of the frame member 157 in front of the injection piston 147.

With the injection piston retracted, the cam 167 con- 'nected with the latch member 166 reaches a position beyond the free end of the lever 180, permitting the latter to be pressed downwardly by the spring 181 so as to dispose the lever end in the path of the vertical edge of the cam 167; As the injection piston thereafter begins its succeeding advancing movement upon admission of hydraulic fluid into the cylinder 142 via the line 143 thereof, the pin 162 moves the slide 163 in the direction of the chute 160. Inasmuch as the cam 167 is in engagement with the end edge of the lever 180, the cam is pivoted in a counterclockwise direction (as seen in FIG. 3) about the axis of the pivot pin 16551, whereby the latch member 166 is angularly moved in the same direction so as to disengage the hooked end thereof from the side member 173 of the lower slide 170. The latter is immediately snapped into its advanced position by the spring 177 so as to introduce the fingers 171 and 172 again into the chute 160. Concurrently therewith, of course, the upper slide 185 is retracted through the intermediary of the link or connecting lever 191, whereby the molding compound biscuit 212b is permitted to drop through the chute onto the fingers 171 and 172.

It will be understood that as the slide 163 moves with the advancing injection piston 147 due to the presence of the pin 162, the latch member 166 and cam 167 are moved angularly (counterclockwise) until the cam slides away from the end edge of the lever 180 so as to reengage the lower edge thereof, at which time the spring 168 again becomes effective to press the hooked end of the latch member against the upper edge of the side member 173 of the slide 170. The arrangement is such that the said hooked end of the latch member will reengage the free end edge of the side member 173 as soon as and only when the injection piston has advanced beyond the aforesaid predetermined point in the injection cylinder 148.

The Ant-Backrndng Means After molding compound has been injected into a mold, the mold wheel 46 is rotated in such a manner as to advance the lled mold to the curing region of the machine. The sudden release of the injection pressure theretofore exerted on the molding compound in the mold cavity, as well as the thermal expansion of the compound in the cavity, tend to bring about an outward flow of the molding compound from the cavity and through the injection sprue or sprues. This outward flow leads to the formation of cavities or craters and like defects, commonly called backrinding, in the molded parts, thereby rendering the same unfit for use or sale. In accordance with the present invention, this potential drawback is eliminated by the anti-backrinding means E which operate to plug the inlet end of each sprue during the entire curing operation, as will now be described in connection with FIGS. l to 8 and l0.

Referring -frst to FIG. 3, it will be remembered that the upper or radially outrmost mold operating rod 84 is hollow and that the end fittings 91 and 99 thereof are provided with respective axial bores 91a and 99a. Extending slidably and rotatably through the rod 84 and the bores 91a and 99a is a shaft 215 to the forwardmost end of which is secured in any suitable manner, as by a nut 21551, an arm 216. The arm 216 at its other end carries a pin or like plug member 217 rigidly afxed to the arm and extending substantailly parallel to the shaft 215. one plug 217 may be mounted on the arm 216 if the sprue elements for the various molds are provided with more than one sprue opening.

As hereinbefore noted, ythe housing 103 connected with the yoke 109 includes, in addition to the sections 103a and 1t}3b constituting parts of the mold opening and closing means C, a section 103C Vwhich is secured to the other sections by the bolts 103:1'.YYY The housing section 183e is provided with a central recess or passageway 218 into which projects that end of the shaft 215 remote from the arm 216. That portion of the passageway 218 which is located immediately adjacent the housing section 103b accommodates a pinion 219 which is rotatable within the housing section 103e but constrained against axial displacement therein. The pinion 219 is connected to the shaft 215 by means of a key 220 the purpose of which is to prevent any relative rotation between the pinion and the shaft while permitting some axial dis placement of the latter relative to and through the pinion 219. The pinion is provided with a plurality of conven- It will be understood, of course, that more than 18 tional gear teeth 21911 (see FIG. l0) and with a peripheral element 219b defining a at surface the function of which will be more fully explained presently.

The shaft `215 is provided at a point spaced from the pinion 219 with a shoulder-defining member 221, e.g. a snap ring, which provides an abutment for the base of a cam sleeve 222, the shaft 215 extending into the central recess 222a of the cam sleeve and being provided adjacent its end with another shoulder-defining ring or washer 223 locked in position by nuts 224. A spring 225 surrounding the shaft 215 is interposed'lbetween the washer 223 and the lbase of the cam sleeve recess 222a and provides a yielding connection Ibetween the cam sleeve 222 and the shaft 215. The cam sleeve 222 is constrained to axial reciprocal movement in the passageway or recess 218 and is prevented from executing any rotary movement by a key 226 provided on a plate or end member 227 secured to the outermost end of the housing section 103C by bolts 22'7a (FIG. 7), the key being adapted to enter a corresponding slot provided in the outer periphery of the cam sleeve 222. As clearly shown in FIG. 7, the cam sleeve is further provided in its outer periphery with a double-faced cam groove 228 into which extends a pin 229 rigidly affixed to a sleeve-shaped pinion 230 slidably surrounding the cam sleeve 222 and arranged in the housing recess 218 for rotational movement only, axial displacement of the pinion 230 ybeing inhibited by the plate member 227 and a shoulder formed in the housing section 103C.

Reciprocally slidable in the housing section 103e at one side of the recess 218 thereof and transversely thereto is a rack 231 the teeth of which mesh with the teeth of the pinion 230 surrounding the cam sleeve 222. On the other side of the passageway 218 in the housing section 103e` there is arranged a plate 232 which is connected at one end with a rack 233 having -teeth meshing with the teeth of the pinion 230, and at the other end with a rack 234 having teeth which mesh with the teeth of the pinion 219. The rack 231 and the rack combination 233-234 are adapted to be shifted within the housing section 103e and radially inwardly of the latterby means of respective piston rods 235 and 236 (FIG. 1) connected with a pair of pistons (not shown) reciprocally arranged in corresponding pneumatic cylinders 237 and 238, the cylinders being provided, respectively, withY fluid lines 237a--237b and 238a-238b. The cylinder 238 is supported by a transverse frame member 239 rigidly connected with the cross member 36 at one side thereof, and the cylinder 237 is supported by a bracket 240 rigidly connected to the opposite side of the cross member 36. As shown in FIG. 2, the piston rod 235 is provided with a transverse arm 241 extending to both sides of the piston rod and adapted to contact not only the upper or radially outermost end of the rack 231 but also .the upper end of the corresponding rack 231 associated with the mold wheel 47. Similarly, the piston rod 236 is provided with a transverse arm (not shown) adapted to engage the rackcarrying plate 232 and its counterpart 232' associated with the mold wheel 47.

The operation of the anti-backrinding means E thus will be seen to be as follows:

When there is no need for plugging up the entranceto a sprue of a mold, the parts are in the positions .thereof illustrated in FIGS. 3 and 7. Thus, the rack 231 is in its elevated position, the rack combination 233-234 is in its lowest position (opposite to that .shown in FIG. 8), the pin 229 is in the outermost end of the cam groove 228, and the shaft 215 is so positioned as to locate the arm 216 in its inoperative position, i.e., extending upwardly toward the cross member 36.

Should it be desired to render the anti-backrinding means operative, `say subsequent to completion of an injection operation, the rack 231'is depressed by the piston rod 235 projecting from the cylinder 237. As the rack 231 moves downwardly as 'seen in FIG. 3, the pinion aerea/ts.;

19 230 is rotated in a clockwise direction as seen from the right hand side of FIGS. 3 and 7. Concurrently therewith the rack combination 233-234 moves upwardly so as to rotate the pinion 219 through an angle sufficient to swing the arm 216 through an angle of 180", whereby to position the pin or plug element 217 in alignment with the sprue of the mold. While this is happening, the engagement between the pin 229 and the cam groove 228 provided in the cam sleeve 222 causes the latter tov be moved axially of itself in a direction away from the housing section 103b, which linear movement is imparted. to the Shaft 215 through the spring 225 and thus serves to bring vthe pin 217 into the entrance to the sprue of the mold. The spring 225 simultaneously acts as a shock4 absorber or cushioning means which` prevents damage to the machine when the pin 217 is brought into solid contact with the mold sprue entrance.

It will be understood that the pinion 219 is constructed to complete the 180 rotation of the shaft 215 and its arm 216 at some time before the pin 229 has completely traversed the cam groove 228, which point of time corresponds to the instant at which the teeth 219a of the pinion 219 go out of mesh with the teeth of the rack 234 while the flat surface 234:1 of the latter cornes into engagement with the correspondingly flat surface of the peripheral gear element 219b. As soon as this happens, further rotation of the shaft 215 and arm 216 isinhibited despite the fact that the rack 234 is still rising due to the continued rotation of the pinion 230 which is necessary and continues until the plug pin 217 is seated in the sprue entrance. At the termination of this movement, the pin 229 is located at the opposite and innermost end of the cam groove 228, while the racks 231, 233 and 234 are in the positions shown in FIGS. 8 and 10.

When it is desired to render the anti-brackrinding means inoperative again, the rack combination 233-234 is moved downwardly from its position shown in FIG. 8 by the piston rod 236 projecting from the cylinder 238. At the beginning of this movement, the pinion 219 does not rotate due to the sliding engagement between the flat surface portion 234a of the rack 234 and the at surface of the pinion element 219b, as a result of which no rotation of the shaft 215 and arm 216 takes place. The pinion 230 is, however, being rotated at this time in a counterclockwise direction as seen from the right-hand side of FIGS. 3 and 7, whereby the cam sleeve moves inwardly of the housing section 103e due to the engagement of the pin 229in the cam groove 228. This linear movement is transmitted to the shaft 215 through the engagement between. the camsleeve and the shoulder-forming snap ring 221, whereby the pin 217 is extracted from the sprue opening. When the shaft has been so linearly moved through a suflicient distance to clear the pin from the top carrier plate 79, the lowest tooth of the rack 234 engages one of the teeth of the pinion 219 and initiates the rotational movement of the latter and thereby the rotation of the shaft 215 and the arm 216 through the desiredV 180 to return the arm to the position thereofl shown in FIG. 3.

The Mold Wheel Indexing Means mold opposite and in alignment wi'ththe associated injec! tion unit. v t

Referring particularly to FIGS. l and 2, it .will be seen that there is loosely mounted on the main shaft 45 intermediate the journal 26 and the hub 4S of the mold wheel 46 an arm 242 which extends downwardly from4 the shaft and carries at its lower end a slide 243 provided with a finger 244 extending toward the mold Wheel 46, the slide 243 being arranged for reciprocal sliding movement lengthwise of the arm by means of suitable guide track means 242a provided in the arm. A spring 243a nor` mally biases the slide 243 upwardly along the arm 242. Fixedly connected with the mold wheel intermediate the latter and the arm 242, as by being welded to the portion 50 of the mold wheel 46, is a gear 245 provided with a plurality of teeth 246. The arrangement is such, as clearly shown in FIG. 2, that the finger 244 of the slide 243 can be moved into and out of the spaces between the gear teeth 246.

The slide 243 carries at its uppermost (radially innermost) end a transverse pin 243b which extends across a recess 242b provided in the arm 242. Slidably engaging the top of the pin 243b is an arm 247a of a rack 247 slidably mounted on the machine frame and having teeth which mesh with the teeth of a pinion 248 rotatably mounted on the machine frame. Also slidably mounted on the machine frame is a locking slide 249 provided with a rack 250 having teeth meshing with the teeth of the pinion 248, the slide 249 being further provided with a tapered finger 251 adapted to be moved into and out of the spaces between the gear teeth 246. Rigidly mounted on the machine frame is a double-acting pneumatic cylinder 252 provided with pressure fluid lines 252a and 252b and with a piston (not shown) connected to a piston rod 253 projecting from the cylinder and carrying at its front end a rack 254 having teeth also meshing with the teeth of the pinion 248.

Articulated to the stanchions 2'3 at one side of the machine frame by means of a pivot pin 255 is a doubleacting hydraulic cylinder 256 having pressure fluid lines 256a and 256b and provided with a piston (not shown) connected to a piston rod 257 projecting from the cylinder toward the arm 242. At its front end, the piston rod 257 is articulated by means of a cross pin 253 to the arm 242 but not directly to the slide 243.

The operation of the mold wheel indexing means, there.-4

fore, is as follows:

When the mold wheel is at rest, the parts are in the: position shown in FIG. l, with the linger 251 of the slide' 249 engaged in the space between two of the gear teeth.

246, whereby the latter and the mold wheel are locked in position and cannot rotate. Should it be desired to index the mold wheel from one position to the next, pressure fluid is` first admitted into the cylinder 252 through` the line 252a thereof to retract the piston rod 253 and the rack 254. The pinion 248 is thus rotated in a clockwise 245` through the intermediary` of the slide 243 which per.-

forms in essence the function of a clutch.

Hydraulic fluid is then admitted into the cylinder 256 through the line 256b to advance the piston rod 257, which causes the arm 242 and therewith the gear 245 and mold wheel 46 to be moved angularly about the axis of the shaft 45. For the purposes of this invention, the stroke of the piston in the cylinder 256 is so predetermined that the arc of this rotary movement corresponds approximately to the pitch of the gear teeth 246 and is such as to move one mold away from the injection unit and bring the next mold into operative position relative to the injection unit. T he. piston rod 253 is thereafter advanced by admission of pressure fluid through the line 252b into the cylinder 252, whereby the rack 254 rotates the pinion 248 in a counterclockwise direction (as seen in FIG. 1) which advances the locking slide 249 radially inwardly 

6. IN AN INJECTION MOLDING MACHINE EQUIPPED WITH AT LEAST ONE MULTI-PLATE MOLD; THE COMBINATION OF MEANS OPERATIVELY CONNECTED WITH SAID MOLD FOR OPENING AND CLOSING THE SAME, MEANS OPERATIVELY CONNECTED WITH SAID OPENING AND CLOSING MEANS FOR APPLYING TO SAID PLATES OF SAID MOLD A HIGH CLAMPING FORCE, AND MEANS COACTING WITH SAID OPENING AND CLOSING MEANS FOR ACTUATING THE LATTER TO DEACTUATE SAID CLAMPING MEANS AND TO OPEN SAID MOLD IMMEDIATELY PRIOR TO EJECTION OF A MOLDED ARTICLE 